Electric comb driven micropump system

ABSTRACT

An electric comb driven micropump system includes a piston, a comb actuator comb and a real-time monitoring device. The comb actuator may generate an electrostatic force after receiving a voltage, so as to actuate the piston to make a first displacement, which causes a fluid to enter into a cavity, wherein the voltage has a voltage value for determining the volume of the fluid entering into the cavity, and wherein as the voltage value of the voltage gradually decreases, the electrostatic forces also decreases, allowing the piston to gradually make a second displacement in a direction opposite to the first displacement driven by a spring, thus outputting the fluid from the cavity. The real-time monitoring device provides real-time information of the comb actuator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a pump technique, morespecifically, a micropump.

2. Description of the Prior Art

Currently, the most commonly seen micropump is valve-less micropump,which primarily uses an actuator to generate vibrations of a membrane,causing changes in volume of a cavity. The inlet and outlet are designedas diffusers/nozzles, the shape thereof controls the fluid input/outputpressures However, current valve-less pumps can only control an averageflow quantity, but not each output quantity. In applications ofbiomedical testing, no quantitative testing can be achieved.

Various researches have been done focusing on changing actuating sourcematerials, the cavity design or valve-type pump etc. For micropumpsystem, Shen-Jian Yang et al. discloses, in TW Patent No. 00568881titled “Programmable capacitive micropump”, a flat rectangularmicro-channel cavity. Top and bottom sides (or just the top side) of thecavity are covered with a elastic membrane plated with a plurality oflinear (grid-shaped) metal electrodes. Applying to each grid-shapedelectrode an appropriate actuating voltage with a phase difference,capacitive electrostatic attraction force generated between thegrid-shaped electrodes and the bottom electrode of the cavity as well aselastic membrane restoring force drives the elastic membrane to generateseveral propagating waves in a single direction, that is, the elasticmembrane pushes fluid in a squirming motion, allowing the micropump tooperate smoothly and effectively.

In TW Patent No. 00324948 titled “electromagnetically actuatedmicropump” by Shi-Chu Chen, an electromagnetically actuated micropump isproposed, which is fabricated by micromachining technique in order toaccurately manipulate microfluid. The micropump has back-and-forthmotions due to electromagnetic actuation in cooperation with valve-lessinlet/outlet. Magnetic forces are generated by a planar coil inconjunction with a soft magnet or a permanent magnet on the samevertical plane. The coil is deposited on a membrane as a moving element,while the magnet acts as a stationary element, or the coil as astationary element and the magnet as the moving element, or two sets ofcoils are used to generate the back-and-forth motions. The design of theinlet/outlet adopts diffuser/nozzle elements instead of the traditionalcheck valves. The micropump having such composition has severaladvantages, such as fast reaction, low input voltage, easy inlet/outletfabrication process and high reliability.

However, the abovementioned micropump systems are all valve-less, whichlacks quantitative output control. Commonly seen piezoelectricvalve-less micropump utilizes piezoelectric plate as the actuatingsource, that is, according to the vibrating principle of thepiezoelectric plate, the membrane is vibrated, causing change in cavityvolume, so that fluid may flow in to/ out of the cavity via thediffusers/nozzles. This is more or less similar to the abovementionedprinciple that outputs fluid by change in cavity volume. This kind ofmethod also requires the design of the diffusers/nozzles to controlfluid output, but not the quantity of the fluid outputted.

SUMMARY OF THE INVENTION

In view of the prior art and the needs of the related industries, thepresent invention provides that solves the abovementioned shortcomingsof the conventional.

One objective of the present invention is to design an electric combdriven micropump system that achieves quantitative fluid output, whichis different from the traditional micropump that continuously but notquantitatively outputs fluid, thus it can be widely used in biochemicalreactions, specimen mixing, lab chips, biological chip quantitativetesting, and various related applications of fluid dynamics.

In view of this and other objectives, the present invention provides anelectric comb driven micropump system, which includes a piston, a combactuator comb and a real-time monitoring device. The comb actuator maygenerate an electrostatic force after receiving a voltage, so as toactuate the piston to make a first displacement, which causes a fluid toenter into a cavity, wherein the voltage has a voltage value fordetermining the volume of the fluid entering into the cavity, andwherein as the voltage value of the voltage gradually decreases, theelectrostatic forces also decreases, allowing the piston to graduallymake a second displacement in a direction opposite to the firstdisplacement driven by a spring, thus outputting the fluid from thecavity. The real-time monitoring device provides real-time informationof the comb actuator.

By using the above electric comb driven micropump system, fluid can beoutputted in fixed quantity desired for testing. Fluid in the cavity canbe pushed out by the piston, thus achieving quantitative output control.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention, andtogether with the description serve to explain the principles of thedisclosure. In the drawings:

FIG. 1 is a cross-sectional schematic diagram of a micropump accordingto a first preferred embodiment of the present invention;

FIGS. 1 to 3 are schematic diagrams illustrating the actuating method ofa micropump according to a second preferred embodiment of the presentinvention;

FIG. 4 is a bottom schematic view of the micropump structure accordingto FIG. 2 of the second preferred embodiment of the present invention;

FIG. 5 is a bottom schematic view of the micropump structure accordingto FIG. 3 of the second preferred embodiment of the present invention;and

FIG. 6 is a schematic diagram of an electric comb driven micropumpsystem.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are described below inconjunction with appended drawings to better understand the above andother objectives, features and advantages of the present invention.

FIG. 1 is a cross-sectional schematic diagram of a micropump accordingto a first preferred embodiment of the present invention. Referring toFIG. 1, the micropump at least comprises a piston 10 and a comb actuator20. The comb actuator 20 may generate an electrostatic force afterreceiving a voltage from a power supply 98 (FIG. 6), so as to actuatethe piston 10 to make a first displacement 12, which causes a fluid 30(FIG. 2) to enter into a cavity 40. The fluid 30 is a sample or areagent, for example.

The abovementioned voltage has a voltage value that determines thevolume of fluid 30 entering into the cavity 40. As the voltage value ofthis voltage gradually decreases, the electrostatic forces alsodecreases, allowing the piston to gradually make a second displacement14 (FIG. 3) in a direction opposite to the first displacement 12 drivenby a spring 70, thus outputting the fluid 30 from the cavity 40. In thisway, the quantity of output of the fluid 30 can be accuratelycontrolled.

The micropump of the first preferred embodiment of the present inventionmay further comprise a voltage control device 80 (e.g. a relay) forgradually reducing the voltage value. The voltage control device 80 mayalso be used to change the voltage value so as to change the volume offluid flowing into the cavity. By using this voltage control device 80,the micropump of the present invention is able to control the quantityof each output. In applications of biomedical testing, the micropump ofthe present invention can provide quantitative specimen.

The cavity 40 of the first preferred embodiment of the present inventionmay be a valve-less cavity. As for the fluid 30, it may be passedthrough an inlet 32 into the cavity 40. Moreover, the fluid 30 insidethe cavity 40 can be outputted via an outlet 34.

There can be a specific angle between the entering direction of theinlet 32 and the exit direction of the outlet 34, such that the flowingdirection of the fluid 30 can be controlled. The specific angle may, forexample, be 90 degrees. The exit direction of the outlet 34 is thedirection of the second displacement 34 of the piston 10. The micropumpmay further comprise a fluid supply and control device connected to aguiding joint. The fluid supply and control device may provide a fixedpressure for driving the fluid in the micropump loop to move in acertain direction. The loop refers to a channel of the micropump inwhich the fluid flows.

FIG. 6 depicts a schematic diagram of an electric comb driven micropumpsystem. Referring to FIG. 6, the comb actuator 20 may be connected to areal-time monitoring device 92 for real-time monitoring of the exterior.This real-time monitoring device 92 may directly monitor the fluid inthe micropump loop so as to provide real-time information to the combactuator 20. More specifically, the real-time monitoring device providesreal-time information by an analog/digital converter 94 (AD/DAconverter) and a computer 96. Based on the real-time information, thevoltage control device 80 can determine the voltage value, and in turnthe volume of fluid to be entered into the cavity 40 (FIG. 1).

Referring now to FIGS. 4 and 5, the micropump of the first preferredembodiment is voltage driven, that is, the displacement of the electriccomb is controlled based on a relationship of the voltage and theelectrostatic force. The fluid is externally driven directly into thevalve-less cavity, then the displacement of the electric comb iscontrolled by varying the voltage, driving the piston 10 to output thefluid 30 inside the cavity 40. The micropump eliminates the problem ofthe valve-less micropump being not able to control the quantity ofoutput. Since the output of the micropump is a total output, thus thedroplet phenomenon can be improved.

The design of the micropump permits the microfluid to be outputted by afixed quantity required for testing. Using principles of diffusers andnozzles, as well as a driving source, the micropump performs piston typeback-and-forth movement, such that the fluid 30 in the cavity 40 ispushed out therefrom by the piston 10 to obtain the required quantity ofoutput.

According to the first preferred embodiment, the present invention canbe widely applied to biochemical reactions, specimen mixing, lab chips,biological chip quantitative testing, and various related applicationsof fluid dynamics. In addition, the present invention employs externalvoltage and pressure control devices and real-time monitoring device forreal-time monitoring reaction status and controlling voltage and output,thus eliminating the shortcoming that traditional chips can only outputcontinuously. The valve-less cavity design also reduces difficulties incontrolling and manufacturing cost.

FIGS. 1 to 3 are schematic diagrams illustrating the actuating method ofa micropump according to a second preferred embodiment of the presentinvention. Referring to FIG. 1, the first step includes guiding a fluid30, by an external fixed driving pressure, via a guiding joint to atemporary tank 90, such that the fluid 30 fills up the tank 90.

FIG. 4 is a bottom schematic view of the micropump structure accordingto FIG. 2 of the second preferred embodiment of the present invention.Referring to FIGS. 2 and 4, the second step includes applying a voltageto a comb actuator 20 to generate an electrostatic force, which actuatesa piston 10 to make a first displacement 12, allowing the fluid 30 toenter into a cavity 40, wherein the voltage has a voltage value fordetermining the volume of the fluid 30 entering into the cavity 40.

Referring to FIGS. 2 and 4, when the voltage value increases, theelectrostatic force generated increases, and in turn the displacement ofthe piston 10 increases accordingly. The first displacement 12 of thepiston is for example an upward movement from the bottom of the cavity40 (FIG. 4; left movement in FIG. 2). Meanwhile, pressure in the cavity40 varies. When the front end of the piston 10 moves to the inlet 32,the cavity will quickly fill up with the fluid 30 due to pressurevariation in the cavity 40, as shown in FIG. 2.

FIG. 5 is a bottom schematic view of the micropump structure accordingto FIG. 3 of the second preferred embodiment of the present invention.Referring to FIGS. 3 and 5, in the third step, voltage value isgradually decreased, so as the electrostatic force, allowing the piston10 to gradually make a second displacement 14 in a direction opposite tothe first displacement 12 driven by a spring 70, thus outputting thefluid 30 from the cavity 40.

The driving voltage applied on the comb actuator 20 gradually decreases,and the comb actuator 20, under the influence of the spring andgradually weakened electrostatic force, drives the piston to make thesecond displacement 14, for example, move downward (FIG. 5; move left inFIG. 3). When the piston 10 moves downward, the fluid 30 is pushedoutside of the cavity 40.

In the second preferred embodiment of the present invention, the aboveactuating method may further comprise a changing step for changing thevoltage value, so as to change the volume of fluid entering into thecavity.

The cavity 40 of the second preferred embodiment of the presentinvention may be a valve-less cavity. As for the fluid 30, referring toFIG. 2, it may be passed through an inlet 32 into the cavity 40.Moreover, the fluid 30 inside the cavity 40 can be outputted via anoutlet 34.

There can be a specific angle between the entering direction of theinlet 32 and the exit direction of the outlet 34, such that the flowingdirection of the fluid 30 can be controlled. The specific angle may, forexample, be 90 degrees. The exit direction of the outlet 34 is thedirection of the second displacement 34 of the piston 10.

According to the second preferred embodiment, the present invention canbe widely applied to biochemical reactions, specimen mixing, lab chips,biological chip quantitative testing, and various related applicationsof fluid dynamics. In addition, the present invention employs externalvoltage and pressure control devices and real-time monitoring device forreal-time monitoring reaction status and controlling voltage and output,thus eliminating the shortcoming that traditional chips can only outputcontinuously. The valve-less cavity design also reduces difficulties incontrolling and manufacturing cost.

The foregoing description is not intended to be exhaustive or to limitthe invention to the precise forms disclosed. Obvious modifications orvariations are possible in light of the above teachings. In this regard,the embodiment or embodiments discussed were chosen and described toprovide the best illustration of the principles of the invention and itspractical application to thereby enable one of ordinary skill in the artto utilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchmodifications and variations are within the scope of the inventions asdetermined by the appended claims when interpreted in accordance withthe breath to which they are fairly and legally entitled.

It is understood that several modifications, changes, and substitutionsare intended in the foregoing disclosure and in some instances somefeatures of the invention will be employed without a corresponding useof other features. Accordingly, it is appropriate that the appendedclaims be construed broadly and in a manner consistent with the scope ofthe invention.

1. An electric comb driven micropump system, including: a piston; a comb actuator comb for generating an electrostatic force after receiving a voltage, so as to actuate the piston to make a first displacement, which causes a fluid to enter into a cavity, wherein the voltage has a voltage value for determining the volume of the fluid entering into the cavity, and wherein as the voltage value of the voltage gradually decreases, the electrostatic forces also decreases, allowing the piston to gradually make a second displacement in a direction opposite to the first displacement driven by a spring, thus outputting the fluid from the cavity; and a real-time monitoring device for providing real-time information of the comb actuator.
 2. An electric comb driven micropump system of claim 1, further including a voltage control device for gradually decreasing the voltage value.
 3. A micropump, including: a piston; and a comb actuator comb for generating an electrostatic force after receiving a voltage, so as to actuate the piston to make a first displacement, which causes a fluid to enter into a cavity, wherein the voltage has a voltage value for determining the volume of the fluid entering into the cavity, and wherein as the voltage value of the voltage gradually decreases, the electrostatic forces also decreases, allowing the piston to gradually make a second displacement in a direction opposite to the first displacement driven by a spring, thus outputting the fluid from the cavity.
 4. A micropump system of claim 3, further including a voltage control device for changing the voltage value, so as to change the volume of the fluid entering into the cavity.
 5. A micropump system of claim 3, wherein the cavity is a cavity with no valve.
 6. A micropump system of claim 3, wherein the fluid enters the cavity through an inlet.
 7. A micropump system of claim 6, wherein the fluid exits the cavity through an outlet.
 8. A micropump system of claim 7, wherein there is a specific angle between the entering direction of the inlet and the exit direction of the outlet, such that the flowing direction of the fluid is controlled.
 9. An actuating method of a micropump, including: applying a voltage to a comb actuator to generate an electrostatic force for actuating a piston, allowing the piston to make a first displacement for causing a fluid to flow into a cavity, wherein the voltage has a voltage value for determining the volume of the fluid entering into the cavity; and gradually decreasing the voltage to reduce the electrostatic forces, allowing the piston to gradually make a second displacement in a direction opposite to the first displacement driven by a spring, thus outputting the fluid from the cavity
 10. An actuating method of a micropump of claim 9, further including a voltage control device for changing the voltage value, so as to change the volume of the fluid entering into the cavity.
 11. An actuating method of a micropump of claim 9, wherein the cavity is a cavity with no valve.
 12. An actuating method of a micropump of claim 9, wherein the fluid enters the cavity through an inlet.
 13. An actuating method of a micropump of claim 12, wherein the fluid exits the cavity through an outlet.
 14. An actuating method of a micropump of claim 3, wherein there is a specific angle between the entering direction of the inlet and the exit direction of the outlet, such that the flowing direction of the fluid is controlled. 